The effects of under- and over-feeding ewes during gestation on offspring growth and stem cell function

Abstract Text:

Poor maternal nutrition during gestation has been linked to poor growth and development, metabolic dysfunction, impaired health, and reduced productivity of offspring in many species. Poor maternal nutrition can be defined as an excess or restriction of overall nutrients or specific macro- or micro-nutrients in the mother’s diet during gestation. Interestingly, there are several reports that both over- and under-feeding during gestation negatively affect offspring postnatal growth with reduced muscle and bone, increased fat, and metabolic dysregulation through reduced leptin and insulin sensitivity. Our laboratory established a model to evaluate both under- and over-feeding during gestation in one population of ewes to evaluate effects on early postnatal growth of offspring. Specifically, ewes were under-fed (60% of NRC for TDN), over-fed (140% of NRC for TDN), or control-fed (100% of NRC for TDN) beginning at d 31 ± 1.3 of gestation. Blood and tissue samples were collected at birth and 3 months of age. As previously reported, during the first 3 months of postnatal growth, over-feeding during gestation increased body size, circulating growth factors and metabolic hormones in offspring. Both under- and over-feeding altered muscle growth, increased lipid content in the muscle and caused changes in expression of myogenic factors. Although the negative effects of poor maternal nutrition on offspring growth have been well characterized in recent years, the mechanisms are not well established. Our laboratory has focused on elucidating these mechanisms by evaluating changes in gene and protein expression and stem cell function. Through RNA-Seq analysis, we observed changes in expression of genes involved in protein synthesis, metabolism, cell function, and signal transduction in muscle tissue. We recently reported that satellite cells, muscle stem cells, have altered expression of myogenic factors in offspring from under-fed mothers. Mesenchymal stem cells, multipotent cells that contribute to development and maintenance of several tissues including bone, muscle and adipose, have a 50% reduction in cell proliferation (P < 0.05) and altered metabolism in offspring from both under- and over-fed mothers. These findings suggest that poor maternal nutrition may alter offspring postnatal growth by programming the stem cell populations. In conclusion, poor maternal nutrition during gestation negatively affects offspring postnatal growth, potentially through impaired stem cell function. Therefore, determining the mechanisms that contribute to fetal programming are critical to identifying novel methods to manage these offspring and improve efficiency of production.

Keywords: maternal nutrition, sheep, stem cells

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